1. Field of the Invention
The present invention relates to a fabrication of a liquid crystal panel constituting a liquid crystal display device, and particularly to a method and an apparatus of scribing a liquid crystal panel and a method of fabricating a liquid crystal panel using the same.
2. Background of the Invention
The liquid crystal display device is an apparatus which displays a desired picture by supplying a data signal based on picture information to liquid crystal cells arranged in a matrix form and controlling an optical transmission rate of the liquid crystal cells. The liquid crystal display device includes a liquid crystal panel in which liquid crystal cells of a pixel unit are arranged in the matrix form and a driving circuit for driving the liquid crystal cells.
The liquid crystal panel includes a first substrate comprising electrodes for applying electric field to liquid crystal cells, a film transistor for switching the supply of data according to each liquid crystal cell, signal lines for supplying data supplied from the exterior to liquid crystal cells; a second substrate comprising color filters; spacers for providing a constant gap between the first and second substrates; and a liquid crystal layer inserted a space provided by the spacer between the first and second substrates.
In the fabrication of the liquid crystal panel, a plurality of film transistor arrays are formed on the first substrate independently. The film transistor arrays are formed such that gate lines are orthogonal to date lines and a film transistor and a pixel electrode are formed at intersecting portions of gate lines and data lines, respectively. The first substrate is adhered to the second substrate which is formed such that a plurality of color filter arrays face the film transistor arrays. The adhered first and second substrates are cut into parts in a constant size and separated into individual unit panels.
The above cell cutting process includes a scribing process and breaking process. The above scribing process is, as shown in FIG. 1A, a process for forming a crack C on a predetermined cutting surface of a substrate 1 using a scribing wheel 2 made of a diamond material higher than a glass substrate 1 in strength. The breaking process is, as shown in FIG. 1B, a process for cutting the substrate 1 by applying a mechanical force through the use of a breaking bar 3, etc., to the substrate 1 on which the crack C is formed.
In addition, at the time of the scribing process, as shown in FIG. 2, not only median cracks (CM) which is a primary factor of substrate cutting but also lateral cracks (CL) in the perpendicular direction with respect to the median cracks CM are formed. The lateral cracks CL do not have any influence on the substrate cutting but rather it weakens strength of the cutting surface. Therefore, it is preferable for the lateral cracks not to be produced if possible.
However, the lateral cracks CL are necessarily produced at the time of scribing process such as the above, and thereby a decline in strength of the cutting surface due to this is a serious problem. As the time passes, the lateral cracks CL grow into a large size and provide a cause of moisture percolation, thereby may be a breakage cause of the liquid crystal display.